1. Field of the Invention
This invention relates generally to vehicular trucks, and more particularly to semi-truck trailers, or truck cargo areas of one piece trucks, having removable side panels which will provide a completely enclosed cargo area so that the truck can be used as a dry van, and yet permit unrestricted side loading thereof and even limited use of the trailer or cargo area as a flat bed.
2. The Prior Art
There are several different forms of truck trailers and truck beds which have differing designs primarily for purposes of carrying loads of different loading and/or hauling requirements. Perhaps the simplest type of truck trailer or cargo area is the flat bed, which merely provides a floor area with no roof or side walls. Flat bed trucks and trailers are primarily used to haul sizable loads which will not be effected by adverse weather conditions, particularly loads that can be more easily loaded with a crane or fork lift truck, such as large pieces of machinery, logs, steel mill products like steel coils, steel plates, steel beams etc., and other comparable loads. The nature of such loads usually require that they be tied down to the flat bed floor with cables or chains.
There are many loads, however, which require the use of dry vans, i.e. closed truck trailers or cargo areas for the purposes of protecting the cargo from adverse weather conditions which may even include refrigeration of perishable goods. Dry vans are perhaps the most common of all truck trailers and cargo areas, and are used to haul all kinds of goods such as home furnishings, clothing, food products and many other products that are not suitable for loading on a flat bed truck. Even products that may not be adversely affected by varying weather conditions may be small enough that they must be hauled in dry vans for purposes of keeping the cargo within a lockable confinement for safe keeping, or simply to confine the cargo to a closure so that it does not need to be tied down or otherwise confined to keep it from falling from the truck bed.
Dry vans are typically provided with doors at the rear end of the trailer or cargo area through which the dry van is loaded and unloaded, which is quite satisfactory for loading and unloading at a conventional loading dock. There are loads, however, which are not particularly amenable to loading through a rear door, particularly elongated loads such as for example, bundles of elongated plastic pipes, finished lumber and the like, which must be loaded either with a crane or side loaded with a fork-lift truck. Accordingly, such loads must normally be hauled on flat bed trucks merely by virtue of the fact that they cannot be readily loaded into a dry van.
While some truck trailers, particularly moving vans, are provided with side doors, the side doors provide a rather limited access opening, being limited to a mid-section on one side of the trailer. Since such side doors are designed primarily for personal access so that the deep end of the trailer can be manually loaded and unloaded without the need of unloading any cargo which may be blocking access through the rear doors of the trailer, the side doors still do not readily permit side loading of the trailer with a fork-lift truck.
Because truck trailers cannot often be used to haul loads of differing hauling or loading requirements, commercial trucks must usually be dedicated to use for hauling only certain limited types of goods. This often results in the fact that a given truck may be driven many miles to deliver a particular load of goods, and then necessarily returned empty because of the inability for that particular truck to accept loads of differing hauling or loading requirements going in the return direction.
The above limited usefulness of trucks, and particularly semi-truck trailers, has been recognized. Indeed, some flat bed truck and trailers are equipped with insertable side panels over which a tarpaulin can be tied. While such a trailer can be utilized as a flat bed and yet provide some form of limited protection of the load from adverse weather conditions, such trailers are clearly not dry vans as rain and winds can still gain access to, and damage the load. As another example, U.S. Pat. No. 4,640,544 discloses a semi-truck trailer having side walls formed by plurality of hinged side-panels over which a tarpaulin can be tied. The side panels are hinged together so that each entire side wall can be folded into the front portion of the trailer, thereby permitting use of the trailer as a flat bed. Such a trailer, however, is not truly wind and water tight, and cannot therefore be utilized as a dry van. In addition, once the side walls are folded into the forward end of the trailer and the load placed on the trailer bed, the walls cannot be repositioned around the load.